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Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

VALDEZ AND SHOUP GLACIERS
255
Valdez Fiord, which testify to great glacial over-deepening of the main fiord. The detailed topographic map made by the U. S. Geological Survey in 1911 and the soundings in Port Valdez by the U. S. Coast and Geodetic Survey,1 from which Fig. 26 has been made, show a number of features characteristic of a trough widened and deepened by glacial erosion. Above sea level the steepened lower slopes and the absence of spurs show the work of the former expanded ice tongue. Below sea level the trough characteristic of the fiord, a flat-bottomed, U-shaped form (Fig. 27), is exactly that of ice-eroded
FIG. 28.   SUBMARINE CONTOURS OF VAIJJHZ ABM.
After U. S. Coast and Geodetic Survey.   Soundings in fathoms.   Contour interval on the land 250 feet, and below sea level 100 feet.
valleys on the land. There are no known, uneroded lateral spurs below sea level. There are several submerged hanging valleys besides Shoup Bay, Sawmill Bay hanging 1150 feet (Fig. 28) and Galena Bay, north of EUamar, 600 feet.
In the narrowest part of Valdez Narrows the fiord walls below sea level have slopes of 2500 feet to the mile, and even more in places.   Here, where the ice stream was most
i Charts 8519 and 8521, U. S. Coast and Geod. Survey.